<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">

    <mx:XML id="myXML" source="http://feeds.feedburner.com/FlexExamples?format=xml" format="e4x" />
    <mx:XMLListCollection id="xlc" source="{myXML..item.category}" sort="{mySort}" />

    <mx:Sort id="mySort">
        <mx:fields>
            <mx:SortField name="*" caseInsensitive="true" />
        </mx:fields>
    </mx:Sort>

    <mx:VBox horizontalAlign="left">
        <mx:Label text="Categories ({xlc.length}):" />
        <mx:List id="list"
                dataProvider="{xlc}"
                rowCount="5"
                width="200"
                creationComplete="{xlc.refresh()}" />
    </mx:VBox>

</mx:Application>